Christmas is a Federal Holiday...If Nothing Else

If the War on Christmas is real (an organized plot effort by the ACLU and their ilk) and if kids aren't allowed to sing Christmas carols or bring red and green plates to school parties...
Is the next step to take away the federal holiday? Post offices, government offices, etc. are not closed for Chanukah, Ramadan or whatever the Muslim holiday is. They are closed for Christmas. If the school is closed for CHRISTMAS, shouldn't you be able to say CHRISTMAS?
Is this just a blue-state problem in the public schools?